"Although I clearly observed Oliver's lips form the three syllables of his name, no sound could be heard to issue forth. Instead, from his mouth dropped what appeared to be a wooden ball of irregular, though roughly spherical, shape."

Sunday, May 15, 2005

On the Use of "Information Talk" in Biology - Useful or Misleading Analogies

[Likewise very drafty - same caveats apply]

Analogies form a vital tool in exploring a new field of study, since they provide a familiar structure into which we can attempt to arrange the new, unfamiliar phenomena. Faced with a structureless bulk of newly-discovered facts, a researcher may well struggle to find the inherent patterns that allow the data to be carved up into simpler blocks, divided into high-level structures and low-level details, and eventually re-described in a new language that allows for a unified understanding. However, if the investigation is guided by an analogy with some other, better-understood part of the world, the process can be accelerated; if we suspect that system XYZ has some structure analogous to known system ABC, and we find find that part X seems to play a role in XYZ like that of part A in ABC, then what could Y be? Quickly a couple of hypotheses suggest themselves...

Of course, the above is only the loosest of sketches of how analogies can guide research[\footnote{For a more careful look at this subject, see [?],[?],and [Corfield]}]. An important fact to note, and a key fact in all that follows in the "biological information" debate, is that analogies can only give us good hypotheses if they themselves are "good" analogies (in a sense to be developed shortly). Of course, hypotheses that turn out to be disconfirmed by the investigations designed to test them can in the long run be useful, if that disconfirming evidence brings with it greater insights. By "good" hypotheses we mean those that bring deeper understanding, those that are confirmed and form part of a more developed theory of the system in question. Such hypotheses are (more likely to be) produced by correct ideas about the structure of the system.

Thus, to provide helpful guidance in our research, we need analogies which point to genuine correspondences with other systems. Moreover, the correspondences should be deep, rather than superficial, picking out important features of the systems referred to. Analogies are better or worse, (very) roughly speaking, depending upon how many features the related systems share, how significant those features are in their respective systems, and how well the relations between those features match up across the comparison. Put another way, good analogies are those that pick out deep abstract structures that are relevantly instantiated in both systems.[\footnote{Disclaimer again: this is necessarily a very rough sketch, but it will suffice.}]